1. Field of the Invention
The present invention relates to a semiconductor device and a method of its fabrication, and more particularly to a semiconductor device that can prevent the occurrence of residue during a repair process, and a method of its fabrication.
2. Description of the Prior Art
In general, a semiconductor device is manufactured by performing a fabrication (FAB) process. For example, a predetermined circuit pattern is repeatedly formed on a substrate to form cells having an integrated circuit. Then an assembly process in which the substrate formed with the cells is packaged into a chip.
Also, an electrical die sorting (EDS) process for examining electrical properties of the cells formed on the substrate may be performed between the FAB process and the assembly process.
Through such an examination process defective cells can be found. And defective cells are replaced with prefabricated redundancy cells by performing a repair process. Thus, all the cells operate normally during actual chip operation, which makes it possible to enhance the yield of the semiconductor device.
In the repair process, a laser beam is irradiated onto a wiring portion connected to the defective cell, thereby breaking off the wiring portion. The wiring to be broken off by the laser beam is called a fuse, and a region in which the fuses cluster together is called a fuse region.
As the integration of semiconductor devices increases, a metal wiring or an electrically conductive layer for a capacitor electrode, which is located in a relatively upper portion within a semiconductor device, is used as the fuse. However, the metal wiring or the electrically conductive layer used as the conventional fuse is problematic in that post-process residues may occur during the repair process, which may cause a leakage current in the semiconductor device.